An American hobby store owned by a billionaire businessman is under fire after refusing to give staff paid sick leave during the COVID-19 pandemic.

Hobby Lobby is an American arts and crafts chain founded by David Green – who has an estimated net worth of $US6.2 billion ($A10.5 billion), according to Forbes.

But in a leaked memo to managers seen by Business Insider, vice president of store operations Randy Betts revealed the company “is going to make every effort to continue working the employees”.

The memo also explained that sick workers – including those who test positive for coronavirus – would have to use personal paid time off and holiday pay or take an “unpaid leave of absence until further notice”.

And if the stores were forced to close due to a government order, staff would have to use “all available paid time off benefits” before gaining access to “emergency pay” which would be three-quarters of their usual wage.

Earlier this month, Mr Green – a devout Christian – also told staff in a letter to brace for tough times ahead.

“To help ensure our company remains strong and prepared to prosper once again when this passes, we may all have to ‘tighten our belts’ over the near future,” he wrote.

“I cannot adequately express how much I appreciate each one of you.”

In the letter, he also claimed that God had communicated with his wife Barbara during a prayer.

“God put on (her) heart three profound words to remind us that he’s in control: Guide, Guard and Groom,” the letter states.

“While we do not know for certain what the future holds, or how long this disruption will last, we can all rest in knowing that God is in control.”